Speedo reading mph?

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bobman12
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Speedo reading mph?

Post by bobman12 » Tue Jul 10, 2018 12:30 am

I just bought a '71 710M in otherwise excellent condition, but I noticed while driving it that it's definitely reading in MPH (radar signs on roads confirm) even though the speedo and odo are still reading kph. They are also definitely original judging by the rust around the ring. So the question is... how was this done (and how to change it back to stock)? Searched the forums but couldn't find anything... thanks!

undysworld
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Re: Speedo reading mph?

Post by undysworld » Tue Jul 10, 2018 6:16 am

bobman12 wrote:
Tue Jul 10, 2018 12:30 am
it's definitely reading in MPH (radar signs on roads confirm) even though the speedo and odo are still reading kph.
Huh? I don't understand your comment. If your speedo and odo are calibrated in km's, what part of the truck is "reading in MPH"?
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rmel
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Re: Speedo reading mph?

Post by rmel » Tue Jul 10, 2018 10:14 am

Hmmm, I think what your saying is that the face plate of the speedo is calibrated kph.

However, your seeing that the needle is lined up at say 50 kph and Radar signs are
telling you your going 50 mph rather than 80.54 kph.

If the odometer is also ticking along in mph and not kph I would suspect that the gearing
in the VDO speedo had to have been changed.

I can't recall where I saw this, but I have stumbled across at least one place that rebuilds
classic VDO speedo's and also sells gear replacement sets. Someone may have gotten cleaver.

And if it's working this way why not leave it :wink:
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bobman12
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Re: Speedo reading mph?

Post by bobman12 » Tue Jul 10, 2018 1:46 pm

Yea so If I'm going 30 mph the speedo needle is at 30 (kph) instead of reading 50 kph.

I haven't yet checked to see if the odometer is logging mph or kph.

Only incentive for me here is to bring it back to stock...

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rmel
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Re: Speedo reading mph?

Post by rmel » Tue Jul 10, 2018 1:50 pm

Obviously, if the odometer still registers in KPM then someone replaced the Speedo faceplate otherwise it’s the internal gears.


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VinceAtReal4x4s
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Re: Speedo reading mph?

Post by VinceAtReal4x4s » Tue Jul 10, 2018 2:06 pm

These guys do all the VDO conversions and calibrations. They are not cheap though.
http://www.nhspeedometer.com/
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rmel
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Re: Speedo reading mph?

Post by rmel » Tue Jul 10, 2018 2:53 pm

Hey! Here's another shop but in a low(er) rent district :wink:

It's not the shop I stumbled onto sometime ago that had VDO replacement gears.

http://seattlespeedometer.com/
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bobman12
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Re: Speedo reading mph?

Post by bobman12 » Fri Jul 13, 2018 2:44 pm

Ok so update on this...

1. The speedo is just wrong, not necessarily MPH.

When it reads 25 KPH it's going about 25-30 MPH
When it reads 45 MPH it's going about 50-60 MPH
At higher speeds the speedo kind of bounces around

2. The odometer is actually dead. Not sure how I missed this before, but it just doesn't move at all.

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rmel
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Re: Speedo reading mph?

Post by rmel » Fri Jul 13, 2018 3:18 pm

That sounds like a weak hairspring, high reading and bouncy.
If you like taking watches apart and fixing them, here's a link
that might be of some help, or time for a new Speedo :wink:

http://dragonflypower.com/VWspeedometerHow2.htm
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bobman12
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Re: Speedo reading mph?

Post by bobman12 » Sat Jul 14, 2018 6:40 pm

Thank you!!

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